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    <title>Document</title>
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    <script>
      // 定义函数
      function rev(arr) {
        var newArr = []
        for (var i = arr.length - 1; i >= 0; i--) {
          newArr.push(arr[i])
        }
        return newArr
      }
      var arr = [1, 2, 3, 4, 5, 6]
      arr = rev(arr)
      console.log(arr)
    </script>
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